[Not Applicable]
1. Field of the Invention
The present invention relates to a multiple layer golf ball. More specifically, the present invention relates to a four-piece golf ball wherein the golf ball has a core, a boundary layer, a wound layer and a cover.
2. Description of the Related Art
Golf balls have evolved throughout the history of the game. The first type of golf balls were the featherie, a leather sphere stuffed with wet, compressed feathers. The next innovation in golf balls was the gutta percha one piece golf ball. As early as the 1800""s, golfers realized that gutta percha golf balls with indented surfaces flew better than those with smooth surfaces. Hand-hammered gutta-percha golf balls could be purchased at least by the 1860""s, and golf balls with brambles (bumps rather than dents) were in style from the late 1800""s to 1908. In 1908, an Englishman, William Taylor, received a patent for a golf ball with indentations (dimples) that flew better and more accurately than golf balls with brambles. A.G. Spalding and Bros., purchased the U.S. rights to the patent and introduced the GLORY ball featuring the TAYLOR dimples. Until the 1970s, the GLORY ball, and most other golf balls with dimples had 336 dimples of the same size using the same pattern, the ATTI pattern. The ATTI pattern was an octahedron pattern, split into eight concentric straight line rows, which was named after the main producer of molds for golf balls. The only innovation related to the surface of a golf ball during this sixty year period came from Albert Penfold who invented a mesh-pattern golf ball for Dunlop. This pattern was invented in 1912 and was accepted until the 1930""s.
Golf balls with a wound layer appeared in the 1920""s, and have been refined since that time. In the 1930""s through the 1960""s, the major innovations in golf balls related to core development. In the 1960""s, the development of ionomer materials, particularly the brand SURLYN(copyright) from Du Pont, became the major innovation for golf balls into the 1980""s. In the 1970""s, dimple pattern innovations also appeared from the major golf ball manufacturers. In 1973, Titleist introduced an icosahedron pattern which divides the golf ball into twenty triangular regions. In the late 1980""s and into the 1990""s, three-piece solid golf balls, as opposed to three-piece wound, began to appear from the major golf ball manufacturers. These three-piece solid golf balls involved two thermoplastic layers covering a core.
Although not commercialized, several patents have disclosed four-piece golf balls. One example is Sun, U.S. Pat. No. 5,273,286 for a Multiple Concentric Section Golf Ball, which was filed in 1992. Sun discloses a golf ball with a solid inner core, a graphite intermediate core, a polybutadiene outer core and a cover composed of balata, ionomer or urethane materials.
Other examples are Hayashi et al., U.S. Pat. No. 5,816,940 for a Wound Golf Ball, which was originally filed in Japan in 1996, and Hayashi et al., U.S. Pat. No. 5,797,808 for a Wound Golf Ball which was originally filed in Japan in 1996. The Hayashi patents disclose a polybutadiene center core, a thermoplastic enclosure layer (preferably an elastomer), a wound layer and a cover composed of an inner layer and an outer layer with both cover layers composed of thermoplastic materials.
Yet another example is Maruko et al., U.S. Pat. No. 5,674,137 which was originally filed in Japan in 1994. Maruko discloses a golf ball with a liquid filled core, a wound layer over the core, and inner and outer cover layers composed of an ionomer material. The primary objective of Maruko is to provide a golf ball with good distance, well-defined spin and greater durability.
A further example is Yabuki et al., U.S. Pat. No. 5,716,293 for a Golf Ball which was originally filed in Japan in 1995. Yabuki discloses a golf ball with a rubber solid core containing an oil substance, an oil-resistant coating layer, a wound layer and an ionomer cover layer.
Another example is Stanton et al., U.S. Pat. No. 5,836,831 for a Golf Ball, originally filed in 1996. Stanton discloses a liquid filled core having a polyether-amide shell, a wound layer and a polymer cover.
There have been many attempts to develop a golf ball that can do everything for every golfer, a golf ball that has tremendous distance, with exceptional feel and outstanding durability. However, current golf balls have been unable to deliver everything.
The present invention provides a golf ball that has tremendous distance, with exceptional feel and outstanding durability. The present invention is able to accomplish this by providing a four-piece wound golf ball with a polyurethane cover.
One aspect of the present invention is a golf ball having a core, a boundary layer, a wound layer and a cover. The solid core is composed of a polybutadiene material and has a distortion of less than 0.138 inch under a constant load of 220 pounds. The core has diameter in the range of 1.35 inches to 1.58 inches. The boundary layer covers the solid core. The boundary layer is composed of a blend of ionomer materials, has a Shore D hardness between 55 and 70 and a thickness in the range of 0.01 inch to 0.1 inch. The wound layer covers the boundary layer and has a thickness of 0.05 inch to 0.1 inch. The cover is composed of a cast thermosetting polyurethane material covering the wound layer. The cast thermosetting polyurethane cover has a thickness in the range of 0.01 inch to 0.05 inch.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.